Add v0.6.0: full skill/agent QA pass, 3 new agents tested, template cleanup

Skills fixed: sprint-status (stale escalation, threshold), retrospective
(existing file detection, missing data fallback), changelog (misc category,
task-ref count), patch-notes (BLOCKED on missing changelog, tone/template
paths), story-readiness (Phase 0 mode resolution, QL-STORY-READY gate),
art-bible, brainstorm, design-system, ux-design, dev-story, story-done,
create-architecture, create-control-manifest, map-systems, propagate-design-change,
quick-design, prototype, asset-spec.

Agents fixed: all 4 directors (gate verdict token format), engine-programmer,
ui-programmer, tools-programmer, technical-artist (engine version safety),
gameplay-programmer (ADR compliance), godot-gdextension-specialist (ABI warning),
systems-designer (escalation path to creative-director), accessibility-specialist
(model, tools, WCAG criterion format, findings template), live-ops-designer
(escalation paths, battle pass value language), qa-tester (model, test case
format, evidence routing, ambiguous criteria, regression scope).

Specs updated: smoke-check and adopt specs rewritten to match actual skill
behavior. catalog.yaml reset to blank template state. Removed
session-state marketing research file, removed session-state from gitignore.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/agents/art-director.md

@@ -101,6 +101,26 @@ Examples:
 - `ui_btn_primary_hover.png`
 - `vfx_[effect]_loop_small.png`
 
+## Gate Verdict Format
+
+When invoked via a director gate (e.g., `AD-ART-BIBLE`, `AD-CONCEPT-VISUAL`), always
+begin your response with the verdict token on its own line:
+
+```
+[GATE-ID]: APPROVE
+```
+or
+```
+[GATE-ID]: CONCERNS
+```
+or
+```
+[GATE-ID]: REJECT
+```
+
+Then provide your full rationale below the verdict line. Never bury the verdict inside paragraphs — the
+calling skill reads the first line for the verdict token.
+
 ### What This Agent Must NOT Do
 
 - Write code or shaders (delegate to technical-artist)